#include<stdio.h>
void menu()
{
    printf("1.add\n");
    printf("2.sub\n");
    printf("3.mul\n");
    printf("4.div\n");
    printf("0.exit\n");
}
int (*pf)[5]={NULL,Add,Sub,Mul,Div};
int main()
{
    int input,x=0,y=0,ret=0;
    do
    {
        menu();
        scanf("%d",&input);
        switch(input)
        {
            case 1:
                printf("please input\n");
                scanf("%d%d",&x,&y);
                ret=Add(x,y);
                printf("%d\n",ret);
                break;
            case 2:
                break;
            case 3:
                break;
            case 4:
                break;
            case 0:
            printf("EXIT!");
                break;
        }
    }while(input);
}